Some search engines may use a mechanism for annotating at least some words of a query with respective labels. In one approach, a search engine may perform this labeling task by consulting static fact tables or a static knowledge base. In another, separate, approach, the search engine may perform the labeling task solely using a sequential model, such as a conditional random field (CRF) model. While the above techniques may provide useful results in some cases, there is room for further improvement in these techniques.